Our research aims at an understanding of lipid metabolism and atherosclerosis through a concerted, multi-discipline approach. Research objectives are: the study of the basic processes of cholesterol and lipoprotein metabolism, transport, and turnover, as related to atherosclerosis; and the long-term clinical evaluation of the partial ileal bypass operation, and adjuvant measures, in the management of patients with hyperlipidemia and atherosclerosis. Our methods include: (1) Clinical evaluation, utilizing serial lipid profile studies; electrocardiography, including treadmill exercise tracings; vectorcardiography; and selective peripheral and coronary arteriography. (2) Test animal and clinical studies of cholesterol absorption, cholesterol and bile acid excretion, cholesterol turnover, and index of cholesterol synthesis, and mathematically calculated cholesterol pool sizes. (3) Sterol extraction from blood, serum, and body tissues. (4) Gross and microscopic studies of animal atherosclerosis. (5) Bioengineering methods, such as viscosity determination at different rates of shear, using a cone-plate viscometer. We are, in addition, subjecting to critical analysis certain phenomenon associated with the jejuno-ileal bypass operation for morbid obesity: The functional and morphological changes, by light and electron microscopy, associated with obesity and subsequent to jejuno- ileal bypass; the incidence of hyperlipidemia in obesity and the response of the circulating lipids to this bypass procedure; the effect of the 90% small intestinal bypass on gastric acid secretion and gastrin production; and the short and long-term effect of jejuno-ileal bypass on vitamin B12 absorption. Bibliographic references: Buchwald, H., Varco, R.L., Moore, R.B., and Schwartz, M. Z.: Intestinal bypass procedures - partial ileal bypass for hyperlipidemia and jejuno-ileal bypass for obesity. Current Prob. in Surg., April 1975; Buchwald, H., Moore, R.B., and Varco, R.L.: Partial ileal bypass operation for control of hyperlipidemia and atherosclerosis. Chapter in Gibbon's Surgery for the Chest, Third Edition, Ed: David C. Sabiston and Frank C. Spencer, Symposia Specialists, 1975.